Question

3. Efetue como achar melhor:
a)( a + 10)(a - 10) =
Sua resposta
b) (5b + 2c)(5b - 2c) =
Sua resposta
c)(x2 + y) (x2 - y) = *
Sua resposta
d)(0,4 - x)(0,4 + x) = *​

Answer 1

Oie, Td Bom?!

a)

$= (a + 10) \: . \: (a - 10) \\ = a {}^{2} - 10 {}^{2} \\ = a {}^{2} - 100$

b)

$= (5b + 2c) \: . \: (5b - 2c) \\ = (5b) {}^{2} - (2c) {}^{2} \\ = 25b {}^{2} - 4c {}^{2}$

c)

$= (x {}^{2} + y) \: . \: (x {}^{2} - y) \\ = (x {}^{2} ) {}^{2} - y {}^{2} \\ = x {}^{4} - y {}^{2}$

d)

$= (0,4 - x) \: . \: (0,4 + x) \\ = 0,4 {}^{2} - x {}^{2} \\ = ( \frac{2}{5} ) {}^{2} - x {}^{2} \\ = \frac{2 {}^{2} }{5 {}^{2} } - x {}^{2} \\ = \frac{4}{25} - x {}^{2}$

Att. Makaveli1996

Answer 2

a)

$\mathsf{(a+10)(a-10)=a^2-10^2=a^2-100}$

b)

$\mathsf{(5b+2c) (5b-2c)=(5b)^2-(2c)^2=25b^2-4c^2}$

c)

$\mathsf{(x^2+y)(x^2-y)=(x^2)^2-(y)^2=x^4-y^2}$

d)

$\mathsf{(0,4-x)(0,4+x)=0,4^2-x^2=0,16-x^2}$